looking at QNAP TS 251 + to replace my HS - 210 as the firmware will no longer updgrate on HS - 210 and following the recent QNAP issues thought it was a good idea - my HS-210 dates from 2014 when I moved over to NAS from CD’s
I only need a 2 bay NAS as I only use for music, 3.5 inch WD drives at the moment which I would prefer to keep
I ran an original 251 for a similar use so the 251+ is more than capable. Swapped mine for a 251d in the end as did not need hdmi etc. Move was seamless, as i my case, the mirror pair could be kept intact so no need for restores etc… best to have a backup prior to undertaking any swap just in case, and test a restore to confirm backup works.
I also ran a plex server on the 251 if you get into movies. it was fine providing the mkv’s did not need transcoding on the fly… native streaming to my tv was perfect so should be ok on the 251+.
I’m curious as to why you would use RAID instead of a backup? If you have a backup to another NAS and run a UPnP server on that you’re fully covered if one of them fails.
Very happy with the TS251+. I’ve had it since 2016 and replaced the 3.5Tb with 8Tb drives. Running Raid1 and HBS3 backup to cloud. Run MinimServer and QVRPro. Obviously I keep it off the internet so use a VPN server to access it remotely.